Tube cleaning apparatus for boilers and the like



Aug. 8, 1944. F. G. w. SPEARS 2,355,570

TUBE CLEANING APPARATUS FOR BOILERS AND THE LIKE Filed June 25, 1942 I Mm s t .m, a MVN N KN Na Q 5 Nmnr Z Q fiE 111..., N \n a NNQ. %N v o. u .7 o .r.. H1 J h% T! mm X\\ \NMK. 6 v Q m Nww\ /\.&A&k QQN T m .o ww QM m iz z Patented Aug. 8, 1944 TUBE CLEANING APPARATUS FOR BOILERS AND THE LIKE Frank George William Spears, Potters Bar, England, assignor of one-half to Charles Fletcher Lumb, Kingston Hill, England Application June 25, 1942, Serial No. 448,458 In Great Britain August 13, 1941 Claims.

This invention relates to apparatus for cleaning boiler tubes and the like, commonly termed soot blowers, of the kind employing a steam ejector which is mounted for movement within a steam chest to assume its operative or inoperative position under the control of an operating member, usually in the form of a screw spindle co-operating with a nut.

The invention has for its object to provide a modified construction and arrangement of the apparatus for obtaining the required movement of the steam ejector.

According to the invention apparatus of the above kind is provided wherein the steam ejector comprises a nozzle slidable within a fixed tubular extension of the steam chest and provided at one end of a tie rod having at its opposite end a piston also slidable with the nozzle within the stem chest'and loosely connected with the said operating member so that the latter is capable of efiecting the desired reciprocation of the steam nozzle, the steam inlet to the steam chest being situated between the piston and the movable element of a valve provided for controlling the admission of the steam to the nozzle.

In the accompanying drawing:

Figure 1 is a longitudinal section of one form of apparatus according to the invention,

Figure 2 is a front view of the steam branch looking upon the common end surface, and

Figure 3 is a cross section on the line 3-3 of Figure 1.

In carrying the invention into efiect in one convenient manner as illustrated in the accompanying drawing, a tube cleaning apparatus is provided comprising a steam chest I, in the form of a tubular casing, to the inner .end of which there is secured, as by screw-threading 2, a valve seat 3 of ring formation and beyond which a tubular extension 4 of the steam chest is provided and secured, as by screw-threading 5, to a steam branch 6 in turn jointed at l to the steam chest by means, for example, of studs 8, and in connection with the joint structure reference may be had to my co-pending application Serial No. 448,459 filed concurrently herewith.

' The steam ejector 9 is accommodated within \the tubular extension 4 of the steam chest and is in the form of a hollow piston having openings ID at its outer end, through which steam is passed to the piston interior, and a nozzle II at its inner end, through which the steam issues and impinges against the tubes to be cleaned. The ejector piston may be fitted with sealing rings l2 and at its outer end the piston is connected by a tie rod I3 with a block l4 forming the movable valve part of a simple shut-down valve, the fixed seat of which is the seat 3 referred to and which movable valve part is in turn connected by another tie rod IS with a piston l6 mounted for movement within the steam chest I.

The apparatus is adapted to be assembled as a unit and, attached to the boiler casing in the manner common to soot blowers but the present construction permits of the whole interior of the apparatus being removed while the connection to the boiler and to themain steam supply is still maintained. That this is so will appear clearer from the remainder of the description of the apparatus but it will be seen from the description already given and from" examination of Figure l of the drawing in particular that it is only necessary to break the joint I, by removal of the nuts 80. and studs 8, to permit the steam chest and with it the entire interior thereof, including the valve seat, movable shut-down valve member and the steam ejector, to be removed.

The construction of the apparatus to provide for the required'movement of the steam ejector is such that the first part of the movement of the ejector into the steam projecting or operative position takes place in a straight line or non-rotary manner and to an extent sufficient to move the shut-down valve from the closed position as shown in Figure l to the fully open position. The steam ejector then partakes of a rotary movement as it continues to be advanced towards the tubes to be cleaned but at that time the ejec- I tor will be receiving a full supply of steam, due to the fully open condition of the Valve.

The piston I6 is formed at its inner end with an annular ledge I! which is presented to the steam admitted to the steam chest through the steam inlet 18, via a 'bore IS in the steam branch 6, and as the area of the ledge is greater than than that of the inner end surface 20 of the shut-down valve [4 or of the ejector 9 at the opposite end .of the steam chest there will be a rearward loading of the piston I6 by the steam, with respect to the direction of flow of the steam tothe ejector 9, and as a consequence the end the nut by the engagement of a bevel wheel on said cap with a bevel wheel 3| rotated in any convenient manner. The cap 28 has an internal central longitudinal bore 32 of rectangular or square cross sectionand the screwed spindle, which passes freely through the said bore, has a squared end part 33 whereby rotation of the cap will cause the screwed spindle to rotate and as it does so the spindle will, by co-operation with the fixed nut 25 be projected forwards, thereby causing pressure to be exerted against the piston It. The squared part 33 will move to and fro along the bore 32 of the cap 28 as the latter is rotated first in one direction and then in the opposite direction, to project or withdraw the steam ejector 9 and by providing a series of interchangeable hollow distance pieces 34 of different widths it is possible by placing the appropriate distance piece loosely upon the screwed spindle to control the extent of the traversal movement of the steam ejector according to particular requirements.

The end face 22 of the plain part 23 of the screwed spindle is joined to the latter by a reduced portion 35 which presents an annular groove 36 within which a stirrup 31 projecting from the interior of the piston is located and by which the traversal movement is imparted to the steam ejector, via the piston 16.

As above stated the first part of the translational movement of the steam ejector into the operative position is merely a straight line or non-rotary motion sufiicient fully to unseat the shut-down valve and this is provided for by a further sleeve extension 38 of the nut being provided with a straight groove 39, that is a groove which is parallel to the longitudinal axis of the apparatus, and by the piston l6 being provided with a stud 40 engageable with the groove 39. The extent of this groove 39 is such as will provide for the complete unseating of the shut-down valve and when this has occurred the stud 49 enters a helical groove 4| on the nut extension 38, formed as acontinuation of the straight groove 39, and for the remainder of the translational movement of the piston I6 and hence of the steam ejector the latter will partake also of a rotary motion. Thus; it follows, that the last part of the return movement of the steam ejector will be accompanied by a simple straight motion sufficient firmly to seat the shut-down valve and therefore close the latter again. The arrangement precludes the possibility of the movable valve member I4 grinding upon its seat 3 and ensures that the steam ejector nozzle receives the full steam supply before rotation thereof commences.

In operation therefore steam enters the steam chest through the branch bore l9 and inlet I 8 and a handle 42 is actuated to rotate the bevel wheels 3|, 30, so that motion is imparted to the screwed spindle 24 by means ofthe square 33 and the valve member [4 is pushed off its seat. The piston l6 (which may be provided with sealing rings 43), tie rods [3, I5 and steam ejector 9 cannot rotate (although they have a tendency to do so due to the friction at A, Figure 1, caused by the steam loading of thepiston in a rearward direction on account of the larger area I! of the piston) until the pin 40 has traversed the straight groove 39. Accordingly the valve member I4 will not grind against its seat 3 during opening, when the valve choke portion 44 prevents escape of the steam, but the straight groove is sufficiently long to equal the length of the valve choke plus the valve lift sufficient to give full steamway before rotation of the steam ejector 9 starts, which will occur when the pin 40 is forced around the spiral scroll 4| due to the continued endwise movement of the screwed spindle, this rotation being assisted by the friction at A.

The piston l 6 serves to balance the steam ejector 9 and, as stated, the angle of rotation is controlled by the travel permitted by the stop bush 34.

A reverse operation of the handle 42 serves to close the valve.

When assembling the screwed spindle in position, prior to the attachment of the nut 25 it is possible to engage the end 22 of the plain part of the spindle behind the stirrup 31 by causing the end to assume a deflected position as shown in dotted lines in Figure 3, after which the spindle will be restored to the horizontal position in which the end 22 is retained behind the stirrup.

The steam branch 6 has the bore l9 through which the steam from the main steam supply pipe fiows to the steam chest and another bore 45 in which the forward end of the steam chest is received and both home terminate at a common end surface 46 of the steam chest, whereby it is possible to effect a steam-tight joint with the corresponding end surface 4'! of the steam chest by the single jointing member 1, which is disposed in one and the same plane. The arrangement permits of the use of the fixed valve seat 3 in rear of the steam inlet [8, having regard to the direction of fiow of the steam, while permitting of the interior of the apparatus being withdrawn without the necessity of breaking the steam joint between the end surface 48 of the steam branch and themain steam supply pipe.

It is to be understood that the invention is not limited to the precise details of construction and arrangement of parts illustrated in the drawing but that these are capable of modification to suit particular requirements and conditions.

I claim:

1. A boiler tube or like cleaning apparatus of the character described including a steam chest in the form of a tubular casing, one end of which is provided with a valveseat, a tubular extension separate from the casing and in alignment therewith and adjacent the valve seat, a steam ejector including a nozzle slidably mounted in the extension and provided with a stem, a valve including a head associated with the valve seat and also provided with a stem and in fixed connection with the stem of the nozzle, a piston in theLsteam chest and in alignment with the valve and the nozzle and fixed tothe stem of the valve, aninternally threaded nut mounted in the end of the casing remote from the valve, an operating spindle passing through said nut and having a threaded portion engaged with the internal screw threads on the nut, interengaging means on the spindle and piston arranged to provide for relative rotative movement between the spindle and piston and to .impart reciprocative movement of the spindle to the piston, and cooperative means between the piston and chest for first guiding the piston in an axial direction and then in a helical direction, and vice versa, depending upon direction of the rotation of the spindle for effecting preliminary opening and final closing of the valve. and the steam chest having a steam inlet opening situated between the valve and the piston.

2. Apparatus as claimed :in'claim 1, in which the piston presents a .greater surface :area to the steam admitted to :the steam chest than that presented at the opposite end of the steam chest whereby a loading of the piston by the steam results in a rearward direction with respect to the valve and in the direction of the operating spindle, with the result that there is a frictional loadcontact of the latter with respect to the piston.

3. Apparatus as claimed in claim 1, in which the internally threaded fixed nut forms a means for closing the outer end of the casing and is provided with external and internal sleeve extensions, the spindle including a threaded portion for cooperation with the threaded portion of the nut and a smooth portion provided with a head, a stirrup on the internal part of the piston for loosely engaging the spindle adjacent the head, the internal extension of the nut having a straight groove and a helical groove, a pin carried internally of the piston for engaging the communicating grooves, and a gear in the form of a cap rotatable Within the external extension of the nut and having a squared bore in which the outer end of the threaded portion of the spindle is fixed so that on rotation of the cap-like gear in either direction the spindle will be actuated to efiect operation of the piston.

4. Apparatus as claimed in claim 1, in which the operating spindle includes a plain portion having a groove near one end to leave a head, an internal stirrup projecting from the piston and arranged in the groove in such manner that the head of the spindle has frictional contact with the center of the piston head and said spindle being arranged in alignment with the stems of the nozzle and the valve.

5. Apparatus as claimed in claim 1, in which the internally threaded fixed nut constitutes a means for closing the outer end of the casing of the steam chest and is provided with an internal sleeve extension surrounding the spindle and positioned within the piston and cooperative means provided on the extension and on the piston for guiding the direction of movement of the piston during operation of the spindle.

FRANK GEORGE WILLIAM SPEARS. 

